I'm cheap, but not that cheap. LOL.
My buddy did that on his chevelle and it works.
Youre carpet may feel stiff due to the two layers, but it does the job. Just illuminate any stink on your old carpet.
I just replaced the whole driver floor board, I bought a foot pump, the old floor board and foot pump bracket where rotted out that I was not able to figure out where the washer foot pump screws down to.